Calabrian walnut cake (torta di noci)
Adapted from a recipe on Food52 from Ada Boni's Regional Italian Cooking (1960)
This is the sort of cake that gets better with age, so is improved by being made ahead of time.
3/4 pound (340 grams or about 3 cups) shelled walnuts
4 eggs, separated
1 cup (225 grams) caster (superfine) sugar
zest of one lemon
icing (confectioners') sugar for dusting (optional)
Pulverize the walnuts in a food processor until you have a coarse meal, the texture of sand.
Grease and line a round 9-inch cake pan.
Beat the egg yolks with the sugar until pale and creamy. Add the lemon zest and walnut meal and stir to combine.
Whisk the egg whites in a separate bowl until they form stiff peaks. Fold the whites bit by bit into the walnut mixture until well combined.
Pour the mixture into the prepared cake pan and bake at 375º F (190º C) for about 50 minutes, or until the top is firm and browned nicely. Let cool completely in the pan before removing and dust with icing sugar to serve.